There are lots of things that we eat that we shouldn't - mostly refined, processed foods. It is great to cut processed foods out of your diet. I have striven to do so over the past six months or so, and have worked towards making food from scratch whenever possible. Usually, my wife and I will make 5 meals from scratch a week (not frozen foods or cans, but raw foods), eat leftovers one day, and eat out on the one remaining day (usually reserved for a day when we both get home from work and don't feel like making food).

There are also things I should probably cut from my diet - refined sugars and flour, for example.

The paleo thing goes too far. Legumes and nuts are good for you (when not coated in sugar, chocolate, oil, etc).

Also, the thing with diets is that if you don't wean yourself onto a diet, but try to jump in with both feet, you'll never succeed. I'm going to try to cut added sugars from my diet this year, but that will be all I do. I'll also probably follow the 80/20 rule - if I'm avoiding added sugars 80% of the time, I don't have to feel bad if I slip up/splurge 20% of the time.